石墨烯自组装

LOGOUnderstandingtheFormationMechanismofGrapheneFrameworksSynthesizedbySolvothermalandRapidPyrolyticProcessesBasedonanAlcohol-SodiumHydroxideSystem学生：刘志学号：15723697汇报内容第一部分：石墨烯的应用及难题第二部分：石墨烯制备步骤第三部分：机理分析第四部分：合成方法比较石墨烯的应用及难题石墨烯产量低生产条件苛刻限制了大规模合成和应用解析其合成机理有利于石墨烯的大规模、低成本、可控的合成和制备石墨烯的制备3.5gNaOH+8mln-propanol200℃36hsolidsolvothermalproductrateof10℃/minfor100mintransfertocombustionboatdecomposeat60℃/sfor60sArstreamcooltoRTwashseveraltimeswithdeionizedwaterfilteredoverdried60℃24hvocuumsamplePS:碳源是其他醇，过程完全相同。是乙酸时，溶剂热反应温度为180℃，裂解温度为1150℃实验分析CharacterizationofGFssynthesizedfromn-propanolandsodiumhydroxide.Pure3Dnetworksconstructedwithgraphenesheets实验分析AFMimageofGFs.Thethicknessisabout3nmforfew-layergraphene.TheRamanspectrumisshowninFigure1d,andtheG-bandat1586cm−1demonstratestheformationofgraphiticcarbon.实验分析Excludingn-propanol,otheralcohols(suchasmethanol,ethanol,andbutanediol)canalsobeusedtoproducegraphene.Thatsuggestsageneralityofthemethodofgraphenesynthesis:Sodiumhydroxidewasusedinsteadofsodium,thedevelopmentprocessbecamemuchsaferandeasier.SEMimagesofGFssynthesisbasedondifferentalcoholsourcesandsodiumhydroxide:(a)methanol,(b)ethanol,and(c)1,4-butanediol.实验分析Alcoholandsodiumhydroxidecanreacttoformsodiumalcoholatesodiumalcoholateinsteadofalcohol+sodiumhydroxide???实验分析sodiumalcoholatecannotinsteadofalcohol+sodiumhydroxide实验分析Poresizedistributionofsolvothermalproductofn-propanolandsodiumhydroxideThesolvothermalproducthadtwoobviousporedistributionsat10~100nmand3~4nm.实验分析TGA-MSanalysisofthesolvothermalproduct:(a,b)n-propanolandsodiumhydroxide;(c,d)ethanolandsodiumhydroxide.小结Aprecursoroftheporousstructureofsodiumalcoholateandalcoholwasformedduringthesolvothermalprocess,andthealcoholinthisstructureplayedasignificantroleinthegrapheneformationduringrapidpyrolysis.实验分析Sodium-containingcompounds,usedasacatalystincoalgasification,canenhancethereactionpotentialandweakentheC−Obondtoimprovethegasificationreactionrateandpromotecarbonconversion.Catalyzingthedecompositionandgasificationofthesolvothermalintermediateduringrapidpyrolysisiseasyfortheremainingsodiuminthesolvothermalproduct.PyrolysisproductviatemperatureprogrammingTheinstantaneoushighinnerpressuregeneratedduringrapidpyrolysisisimportantingrapheneformation.Whenthepressureishighenough,thestackcanbeeffectivelyrestrainedduringtheself-assemblyofcarbonatoms,whichleadstotheformationofgrapheneinsteadofgraphite.实验分析(a)X-raydiffractionpatternofas-preparedGFsobtainedfromtherapiddecompositionofthesolvothermalproductsofn-propanolandsodiumhydroxideat1000°C.DetectedMSsignals:(b)CO2,(c)H2O,and(d)COviafloatingCVD.Thesefindingssuggestedthatsodium-containingmaterialscanenhancethedecompositionandgasificationofsolvothermalproductsduringrapidpyrolysis.小结实验分析(a)XPSsurveyspectrumofGFs.(b)O1sspectrumofGFs.实验分析结论GFs的组装机理总结如下：在溶剂热反应中1.初步形成多孔的前驱物2.有有机物的剩余这使得在快速裂解过程中会迅速产生很高的内部高压在快速裂解过程中1.高温和Na催化的过程中，前驱物迅速裂解产生大量碳原子2.由于大量醚键的限制，石墨烯自组装成3D框架结构理论上说：能够形成富氧多孔前驱物的材料就可以合成GFs，这并不仅限于醇。（已通过乙酸+氢氧化钠体系证明）合成方法比较template-directed-------3Dmacroporousbubblegraphene----anaverageporediameterof107.3nmnucleateboilingmethod------foamlikegraphenestructures------poorermechanicalstabilityoftheframeworkstructure.chemicalvapordeposition-----3Dgraphenenetworks--------wettabilityispoor-----unfavorabletoapplyinelectrodematerials合成方法比较优势：更好的电化学超级电容器性能原因：1.较大的比表面积区能吸收更多的电解质2.拥有含氧官能团，具有较好的润湿性3.结构合理的框架结构，能减少扩散长度，提供多重离子或电子迁移路线结论汇报内容第一部分：石墨烯的应用及难题第二部分：石墨烯制备步骤第三部分：机理分析第四部分：合成方法比较Thanksforyourattention